diff --git a/llvm/include/llvm/IR/PatternMatch.h b/llvm/include/llvm/IR/PatternMatch.h
--- a/llvm/include/llvm/IR/PatternMatch.h
+++ b/llvm/include/llvm/IR/PatternMatch.h
@@ -2446,6 +2446,11 @@
   return LogicalOp_match<LHS, RHS, Instruction::And>(L, R);
 }
 
+template <typename LHS, typename RHS>
+inline auto m_c_LogicalAnd(const LHS &L, const RHS &R) {
+  return m_CombineOr(m_LogicalAnd(L, R), m_LogicalAnd(R, L));
+}
+
 /// Matches L || R either in the form of L | R or L ? true : R.
 /// Note that the latter form is poison-blocking.
 template <typename LHS, typename RHS>
@@ -2459,6 +2464,11 @@
   return m_LogicalOr(m_Value(), m_Value());
 }
 
+template <typename LHS, typename RHS>
+inline auto m_c_LogicalOr(const LHS &L, const RHS &R) {
+  return m_CombineOr(m_LogicalOr(L, R), m_LogicalOr(R, L));
+}
+
 } // end namespace PatternMatch
 } // end namespace llvm
 
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4859,6 +4859,10 @@
     if (match(I, m_ExtractValue(m_WithOverflowInst(II))) &&
         match(ValAssumedPoison, m_ExtractValue(m_Specific(II))))
       return true;
+
+    // 'select ValAssumedPoison, _, _' is poison.
+    if (match(I, m_Select(m_Specific(ValAssumedPoison), m_Value(), m_Value())))
+      return true;
   }
   return false;
 }
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2628,6 +2628,25 @@
     if (match(FalseVal, m_Not(m_Specific(CondVal))))
       return SelectInst::Create(FalseVal, ConstantInt::getTrue(SelType),
                                 TrueVal);
+
+    // select a, (a /\ b), false -> select a, b, false
+    Value *A, *B;
+    if (match(TrueVal, m_c_LogicalAnd(m_Specific(CondVal), m_Value(B))) &&
+        match(FalseVal, m_Zero()))
+      return replaceOperand(SI, 1, B);
+    // select a, true, (a \/ b) -> select a, true, b
+    if (match(TrueVal, m_One()) &&
+        match(FalseVal, m_c_LogicalOr(m_Specific(CondVal), m_Value(B))))
+      return replaceOperand(SI, 2, B);
+
+    // select (select a, true, b), true, b -> select a, true, b
+    if (match(CondVal, m_Select(m_Value(A), m_One(), m_Value(B))) &&
+        match(TrueVal, m_One()) && match(FalseVal, m_Specific(B)))
+      return replaceOperand(SI, 0, A);
+    // select (select a, b, false), b, false -> select a, b, false
+    if (match(CondVal, m_Select(m_Value(A), m_Value(B), m_Zero())) &&
+        match(TrueVal, m_Specific(B)) && match(FalseVal, m_Zero()))
+      return replaceOperand(SI, 0, A);
   }
 
   // Selecting between two integer or vector splat integer constants?
diff --git a/llvm/test/Transforms/InstCombine/select-safe-bool-transforms.ll b/llvm/test/Transforms/InstCombine/select-safe-bool-transforms.ll
--- a/llvm/test/Transforms/InstCombine/select-safe-bool-transforms.ll
+++ b/llvm/test/Transforms/InstCombine/select-safe-bool-transforms.ll
@@ -1,9 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -instcombine-unsafe-select-transform=0 -instcombine -S | FileCheck %s
 
-; TODO: All of these should be optimized to a single instruction of select/
-; and/or.
-
 ; 1. --- X /\ (X /\ Y) ---
 
 define i1 @merge_logical_and_and(i1 %X, i1 %Y) {
@@ -28,8 +25,7 @@
 
 define i1 @merge_and_logical_and(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_and_logical_and(
-; CHECK-NEXT:    [[C:%.*]] = and i1 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X]], i1 [[C]], i1 false
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X:%.*]], i1 [[Y:%.*]], i1 false
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = and i1 %X, %Y
@@ -52,8 +48,8 @@
 
 define i1 @merge_two_logical_ands2(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_two_logical_ands2(
-; CHECK-NEXT:    [[TMP1:%.*]] = and i1 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    ret i1 [[TMP1]]
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X:%.*]], i1 [[Y:%.*]], i1 false
+; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = select i1 %Y, i1 %X, i1 false
   %res = select i1 %X, i1 %c, i1 false
@@ -62,8 +58,7 @@
 
 define i1 @merge_and_logical_and2(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_and_logical_and2(
-; CHECK-NEXT:    [[C:%.*]] = and i1 [[Y:%.*]], [[X:%.*]]
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X]], i1 [[C]], i1 false
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X:%.*]], i1 [[Y:%.*]], i1 false
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = and i1 %Y, %X
@@ -86,8 +81,7 @@
 define i1 @merge_two_logical_ands3(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_two_logical_ands3(
 ; CHECK-NEXT:    [[C:%.*]] = select i1 [[X:%.*]], i1 [[Y:%.*]], i1 false
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[C]], i1 [[X]], i1 false
-; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK-NEXT:    ret i1 [[C]]
 ;
   %c = select i1 %X, i1 %Y, i1 false
   %res = select i1 %c, i1 %X, i1 false
@@ -120,8 +114,7 @@
 
 define i1 @merge_two_logical_ands4(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_two_logical_ands4(
-; CHECK-NEXT:    [[C:%.*]] = select i1 [[Y:%.*]], i1 [[X:%.*]], i1 false
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[C]], i1 [[X]], i1 false
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[Y:%.*]], i1 [[X:%.*]], i1 false
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = select i1 %Y, i1 %X, i1 false
@@ -165,8 +158,7 @@
 
 define i1 @merge_or_logical_or(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_or_logical_or(
-; CHECK-NEXT:    [[C:%.*]] = or i1 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X]], i1 true, i1 [[C]]
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X:%.*]], i1 true, i1 [[Y:%.*]]
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = or i1 %X, %Y
@@ -189,8 +181,8 @@
 
 define i1 @merge_two_logical_ors2(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_two_logical_ors2(
-; CHECK-NEXT:    [[TMP1:%.*]] = or i1 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    ret i1 [[TMP1]]
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X:%.*]], i1 true, i1 [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = select i1 %Y, i1 true, i1 %X
   %res = select i1 %X, i1 true, i1 %c
@@ -199,8 +191,7 @@
 
 define i1 @merge_or_logical_or2(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_or_logical_or2(
-; CHECK-NEXT:    [[C:%.*]] = or i1 [[Y:%.*]], [[X:%.*]]
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X]], i1 true, i1 [[C]]
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[X:%.*]], i1 true, i1 [[Y:%.*]]
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = or i1 %Y, %X
@@ -223,8 +214,7 @@
 define i1 @merge_two_logical_ors3(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_two_logical_ors3(
 ; CHECK-NEXT:    [[C:%.*]] = select i1 [[X:%.*]], i1 true, i1 [[Y:%.*]]
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[C]], i1 true, i1 [[X]]
-; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK-NEXT:    ret i1 [[C]]
 ;
   %c = select i1 %X, i1 true, i1 %Y
   %res = select i1 %c, i1 true, i1 %X
@@ -257,8 +247,7 @@
 
 define i1 @merge_two_logical_ors4(i1 %X, i1 %Y) {
 ; CHECK-LABEL: @merge_two_logical_ors4(
-; CHECK-NEXT:    [[C:%.*]] = select i1 [[Y:%.*]], i1 true, i1 [[X:%.*]]
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[C]], i1 true, i1 [[X]]
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[Y:%.*]], i1 true, i1 [[X:%.*]]
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %c = select i1 %Y, i1 true, i1 %X